cycling of matter and energy

Question 1

biogeochemical overview

Answer 1

• Matter is recycled within and between ecosystems
  - Every organism needs nutrients to build tissues and other life functions
• Biogeochemical Cycles - closed loops that cycle matter through biological, geological, and chemical processes
  
  • Matter is transformed (never destroyed nor created)

Question 2

water cycle

Answer 2

• Precipitation
  - rain/snow/sleet/hail that falls to the ground
• Surface Runoff
  
  • Excess liquid flows across the surface of land and into nearby creeks/streams/ponds
• Percolation
  
  • When runoff filters through the soil
• Evaporation
  
  • Process that changes liquid water and into gas (water vapor)
• Transpiration
  
  • When water vapor from leaves goes to atmosphere
• Condensation
  
  • Conversion of vapor or gas to a liquid
• HUMAN ACTIVITY
  
  • Fertilizers that stream into lakes with high nitrogen concentration
  • Pollution in run-off is poured into streams

Question 3

nitrogen cycle

Answer 3

• Nitrification: When certain bacteria convert various forms of N-containing compounds (i.e. ammonia) in the soil into nitrates and nitrites
  - Nitrogen gas most abundant form of nitrogen on Earth
  - Only bacteria can use this form directly
  - Bacteria live in soil and on roots of legumes
  - nitrates/nitrites are used up by primary products for proteins and nucleic acids
  - Consumers reuse nitrogen to make own nitrogen-containing compounds by eating the producers
• Deamination: decomposers release nitrogen from waste and dead organisms as ammonia, nitrates, and nitrites that producers may take in again
• Nitrogen Fixation: When certain bacteria convert nitrogen gas into ammonia (lightning can also perform nitrogen fixation)
  
  • This fixed nitrogen is converted into nitrates and nitrites in nitrification
• Denitrification: When bacteria convert nitrates into nitrogen gas which is released into the environment
  
  • Bacteria do this to obtain energy

Question 4

carbon cycle

Answer 4

• Carbon atoms are found and recycled in reservoirs
• Carbon-storing Reservoirs
  
  • Plants
    - Take in CO2 to make carbohydrates and released through respiration
  • Atmosphere
  • Deep/Surface Oceans
    - CO2 is continuously exchanged between atmosphere and ocean
  • Fossil Fuels
    - Geological forced take accumulated carbon and turn it into fossil fuels over the course of thousands of years
  • Animals
  • Dead organisms (using decomposers) release carbon into the environment
  • Soil
• Combustion - burning of fossil fuels that release carbon dioxide into the atmosphere

Question 5

food webs and energy pyramids

Answer 5

• Matter and energy can not be created nor destroyed
  - Decomposers recycle matter back to producers
  - Energy is used but largely lost as heat
• Energy flows in one direction (producers to heterotrophs)
• Food Chain: a hierarchical series of organisms each dependent on the next as a source of food
• Food Web: an interlocking pattern of food chains

Question 6

pyramid of energy

Answer 6

• Relative of energy at each trophic level
• greatest amount of energy found at base of food web (producers)
• least amount of energy found at top of food web (top consumer)
• Rule of 10: every trophic level you go up you divide the amount of energy by 10 because the majority of energy is as heat

Question 7

pyramid of biomass

Answer 7

• Shows amount of biomass in each trophic level
• Biomass - total weight of all organisms in a specific area
  
  • Measured in grams/square meters (g/m2)
• Majority of biomass is at bottom and is made up of producers
• Amount of energy available can determine amount of biomass

Question 8

pyramid of numbers

Answer 8

• Shows relative number of organisms in each trophic level
• Consumers are much smaller in mass and size than the organisms they feed upon
  
  • (i.e. if thousands of insects are grazing on the same tree, the pyramid of numbers will be inverted because a single tree has more biomass than the insects that fee upon it